// Copyright (C) 2017 Jonathan Müller <jonathanmueller.dev@gmail.com>
// This file is subject to the license terms in the LICENSE file
// found in the top-level directory of this distribution.

#ifndef CPPAST_CPP_FRIEND_HPP_INCLUDED
#define CPPAST_CPP_FRIEND_HPP_INCLUDED

#include <type_safe/optional.hpp>

#include <cppast/cpp_entity.hpp>
#include <cppast/cpp_entity_container.hpp>
#include <cppast/cpp_type.hpp>

namespace cppast
{
    /// A [cppast::cpp_entity]() representing a friend declaration.
    ///
    /// It can either declare or define a `friend` function (template), declare a `friend` class,
    /// or refer to an existing type.
    class cpp_friend : public cpp_entity, private cpp_entity_container<cpp_friend, cpp_entity>
    {
    public:
        static cpp_entity_kind kind() noexcept;

        /// \returns A newly created friend declaring the given entity as `friend`.
        /// \notes The friend declaration itself will not be registered,
        /// but the referring entity is.
        static std::unique_ptr<cpp_friend> build(std::unique_ptr<cpp_entity> e)
        {
            return std::unique_ptr<cpp_friend>(new cpp_friend(std::move(e)));
        }

        /// \returns A newly created friend declaring the given type as `friend`.
        /// \notes It will not be registered.
        static std::unique_ptr<cpp_friend> build(std::unique_ptr<cpp_type> type)
        {
            return std::unique_ptr<cpp_friend>(new cpp_friend(std::move(type)));
        }

        /// \returns An optional reference to the entity it declares as friend, or `nullptr`.
        type_safe::optional_ref<const cpp_entity> entity() const noexcept
        {
            if (begin() == end())
                return nullptr;
            return type_safe::ref(*begin());
        }

        /// \returns An optional reference to the type it declares as friend, or `nullptr`.
        type_safe::optional_ref<const cpp_type> type() const noexcept
        {
            return type_safe::opt_ref(type_.get());
        }

    private:
        cpp_friend(std::unique_ptr<cpp_entity> e) : cpp_entity("")
        {
            add_child(std::move(e));
        }

        cpp_friend(std::unique_ptr<cpp_type> type) : cpp_entity(""), type_(std::move(type))
        {
        }

        cpp_entity_kind do_get_entity_kind() const noexcept override;

        std::unique_ptr<cpp_type> type_;

        friend cpp_entity_container<cpp_friend, cpp_entity>;
    };
} // namespace cppast

#endif // CPPAST_CPP_FRIEND_HPP_INCLUDED